Eight-claw automobile generator without magnetic strips

Abstract

The utility model discloses an eight-claw automobile generator without magnetic stripes, and aims to solve the problems of high cost, low efficiency and poor stator winding heat dissipation of a traditional six-pair claw pole permanent magnet generator. Comprising a rotor assembly (8-claw-pole permanent-magnet-free) and a stator assembly (rectangular copper wire winding). The rotor adopts eight alternately arranged claw poles, a magnetic field is generated through energization of an excitation winding, a permanent magnet is omitted, and the cost is reduced; the eight-claw pole structure enables the magnetic field to be denser and improves the armature cutting efficiency; rectangular copper wires are embedded in the stator slots and are tightly arranged, so that the slot fullness rate is increased, and the heat dissipation area is increased. Therefore, the output power of the generator is equal to that of a traditional six-pair claw pole permanent magnet generator, but the cost is reduced, the magnetic attenuation risk is avoided, and the reliability is better.

Description

Technical Field

[0001] This utility model relates to the field of automotive generator technology, specifically to a claw-pole excitation generator, and more particularly to an eight-pole permanent magnet-free excitation generator that achieves high-efficiency and low-cost operation by optimizing the claw-pole structure and stator winding design. Background Technology

[0002] Traditional claw-pole excitation generators typically employ a rotor structure with six pairs of claw poles, embedding permanent magnets between the claw poles to enhance the magnetic field and thus improve power generation efficiency. However, this structure has the following drawbacks:

[0003] 1. Permanent magnets are expensive and highly susceptible to fluctuations in the price of rare earth materials;

[0004] 2. The magnetic field distribution of the 6-pair claw pole structure is sparse, and the armature winding has low efficiency in cutting the magnetic lines, so it needs to rely on permanent magnets to compensate for the power.

[0005] 3. Stator windings are mostly made of round copper wire. The round copper wires are irregularly arranged in the stator slots, resulting in low slot fill factor (usually ≤70%) and small heat dissipation area, which makes the insulation prone to aging due to high temperature.

[0006] 4. Permanent magnets have magnetic attenuation issues, which cause a significant decrease in generator power after long-term use.

[0007] Therefore, there is an urgent need for a new type of claw-pole excitation generator that is low-cost, highly efficient, and more reliable. Utility Model Content

[0008] To address the aforementioned issues, the purpose of this invention is to provide an eight-pole automotive generator without magnetic strips. By eliminating permanent magnets and optimizing the number of claw poles and stator winding structure, the cost is reduced, magnetic cutting efficiency and heat dissipation performance are improved, while maintaining or increasing the power of the original six-pole generator with permanent magnets.

[0009] To achieve the above objectives, this utility model provides the following technical solution: an eight-pole claw-type excitation generator without permanent magnets, comprising a rotor assembly, a stator assembly, and a front / rear cover (not shown in the figure); the rotor assembly includes a rotating shaft, symmetrically arranged eight-pole sleeves, and an excitation winding; the stator assembly includes a stator core and rectangular copper wire windings in the stator slots; each of the two eight-pole sleeves has eight claw poles; in the rotor assembly, the eight-pole sleeves are fixed to the rotating shaft by pole shoes made of non-magnetic material (such as aluminum alloy), and the two eight-pole sleeves interlock to form a magnetic gap between adjacent claw poles; the excitation winding is wound in the excitation slots of the rotating shaft, and after being energized, it forms an alternating magnetic field by magnetizing the magnetic gap through the claw poles;

[0010] In the stator assembly, the stator core has 96 stator slots evenly distributed along the circumference (the number can be adjusted according to the power), and each stator slot is embedded with a rectangular copper wire winding; the cross-sectional aspect ratio of the rectangular copper wire is 2:1 to 4:1, and they are closely arranged along the axial direction of the stator slot, with the sides of adjacent rectangular copper wires touching, and the slot fill factor is ≥85%;

[0011] The radial length of the eight claw poles of the octagonal sleeve matches the radial length of the stator core, ensuring that the claw pole magnetic field covers all effective conductors of the stator winding; the thickness direction of the rectangular copper wire is consistent with the depth direction of the stator slot, and the width direction extends radially along the stator slot, increasing the heat dissipation surface area.

[0012] Further design optimization:

[0013] 1. The arc coefficient of the claw pole is 0.6~0.7 (0.5~0.6 for the original 6-pair claw pole), which increases the magnetic field coverage area of ​​a single claw pole and improves the frequency and density of the armature winding cutting the magnetic lines.

[0014] 2. The rectangular copper wire has an insulating layer (such as a polyimide film) on its surface, and adjacent copper wires are isolated by the insulating layer to avoid short circuits;

[0015] 3. The stator core is made of stacked silicon steel sheets with insulating varnish applied between the sheets to reduce iron loss;

[0016] 4. The excitation winding is made of flat copper wire, with a higher turn density than traditional round copper wire winding, thus reducing the amount of copper used.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. Cost reduction: The permanent magnet is eliminated, and only the excitation winding needs to be energized to generate a magnetic field, avoiding the maintenance costs caused by the purchase of permanent magnets and magnetic attenuation;

[0019] 2. Improved efficiency: The eight-pole structure of the eight-pole sleeve makes the magnetic gap magnetic field more concentrated, and the frequency of the armature winding cutting the magnetic line increases by 15%-20%. Under the same excitation current, the output power is basically the same as that of the original 6-pole permanent magnet generator.

[0020] 3. Slot fill factor optimization: The rectangular copper wires are closely arranged, which improves the slot fill factor, reduces ineffective space, and lowers the winding resistance;

[0021] 4. Enhanced heat dissipation: The large surface area design of the rectangular copper wire improves the heat dissipation efficiency of the stator winding by more than 30%, avoids insulation aging caused by high temperature, and extends the generator life.

[0022] 5. Reliable structure: The absence of permanent magnets avoids the risk of magnets falling off, and the claw poles and pole shoes are fixed with non-magnetic materials, making the assembly process simpler.

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of a specific embodiment of the present utility model;

[0025] Figure 2 This is a structural diagram of the stator assembly in a specific embodiment of the present invention;

[0026] Figure 3 This is a side view of the stator assembly in a specific embodiment of the present invention;

[0027] Figure 4 This is a structural diagram of the stator core in a specific embodiment of this utility model.

[0028] The markings in the diagram are: 1-rotor assembly; 2-stator assembly; 3-shaft; 4-octagonal sleeve; 41-claw pole; 5-pole shoe; 6-excitation winding; 21-stator core; 7-stator slot; 8-rectangular copper wire. Detailed Implementation

[0029] The present invention will be described in detail below through embodiments, which are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0030] like Figure 1 — Figure 4 As shown, this embodiment discloses an eight-claw automotive generator without magnetic strips, including a rotor assembly 1, a stator assembly 2, a front cover (not shown in the figure), and a rear cover (not shown in the figure).

[0031] In the rotor assembly, two symmetrically arranged eight-claw sleeves 4 are fixed on the rotating shaft 3. The two eight-claw sleeves 4 are closely interlocked, so that 8 N poles and 8 S poles of the 16 claw poles 41 are arranged alternately. The eight-claw sleeves 4 are fixed to the rotating shaft 3 by welding with aluminum alloy pole shoes 5 to ensure magnetic circuit sealing. The excitation winding 6 is wound in the excitation slot of the rotating shaft 3 (not shown in the figure). After being energized, it generates an axial magnetic field, which is magnetized by the claw poles 41 and forms an alternating magnetic field in the magnetic gap between adjacent claw poles 41.

[0032] In stator assembly 2, stator core 21 is formed by stacking silicon steel sheets, and 96 stator slots 7 are evenly distributed along the circumference; each stator slot 7 is embedded with a rectangular copper wire 8 (length to width ratio 2:1), the surface of the rectangular copper wire 8 is coated with a polyimide insulation layer, and they are closely arranged along the slot axis (adjacent copper wires are side-to-side), and the slot fill factor is calculated as (total cross-sectional area of ​​copper wires / cross-sectional area of ​​stator slot) × 100% ≈ 88%; the thickness direction of the rectangular copper wire is consistent with the depth direction of the stator slot, and the width direction extends radially along the stator slot to increase the contact area with air.

[0033] During operation, the excitation winding 6 generates an axial magnetic field, which, after being magnetized by the 16 claw poles 41, forms a dense alternating magnetic field. When the rotor rotates, the frequency at which the stator winding (rectangular copper wire 8) cuts the magnetic field lines is increased by 18% compared to the original 6-claw pole structure, resulting in a greater induced electromotive force per unit time. The high slot fill factor of the rectangular copper wire reduces the winding resistance and decreases copper losses. At the same time, the large surface area of ​​the rectangular copper wire 8 accelerates heat dissipation, preventing the winding from overheating. Actual test data shows that this generator outputs 1200W at a speed of 1000r / min, which is the same as the original 6-claw pole 41 generator with permanent magnets (1200W), but at a 25% lower cost and without the problem of permanent magnet magnetic decay.

[0034] The following technical effects can be achieved by using the above technical solution:

[0035] 1. Cost reduction: The permanent magnet is eliminated, and only the excitation winding needs to be energized to generate a magnetic field, avoiding the maintenance costs caused by the purchase of permanent magnets and magnetic attenuation;

[0036] 2. Improved efficiency: The eight-pole structure of the eight-pole sleeve makes the magnetic gap magnetic field more concentrated, and the frequency of the armature winding cutting the magnetic line increases by 15%-20%. Under the same excitation current, the output power is basically the same as that of the original 6-pole permanent magnet generator.

[0037] 3. Slot fill factor optimization: The rectangular copper wires are closely arranged, and the slot fill factor is increased from ≤70% to ≥85%, reducing ineffective space and lowering winding resistance;

[0038] 4. Enhanced heat dissipation: The large surface area design of the rectangular copper wire improves the heat dissipation efficiency of the stator winding by more than 30%, avoids insulation aging caused by high temperature, and extends the generator life.

[0039] 5. Reliable structure: The absence of permanent magnets avoids the risk of magnets falling off, and the claw poles and pole shoes are fixed with non-magnetic materials, making the assembly process simpler.

Claims

1. An octagonal automotive generator without a magnetic strip, characterized in that: The system includes a rotor assembly (1) and a stator assembly (2); the rotor assembly (1) includes a rotating shaft (3), symmetrical eight-claw sleeves (4) and an excitation winding (6); the stator assembly (2) includes a stator core (21) and a rectangular copper wire (8) winding in the stator slot (7); the two eight-claw sleeves (4) each have 8 claw poles, and the eight-claw sleeves (4) are fixed to the rotating shaft (3) by non-magnetic pole shoes (5), and the two eight-claw sleeves (4) are close together in an interlocking manner to form a magnetic gap between adjacent claw poles; the excitation winding (6) is wound in the excitation slot of the rotating shaft (3), and after being energized, it forms an alternating magnetic field by magnetizing the magnetic gap through the claw poles; the stator core (21) has multiple stator slots (7) distributed along the circumference, and each stator slot (7) is embedded with a rectangular copper wire (8), and the aspect ratio of the rectangular copper wire (8) is 2:1 to 4:

1.

2. The eight-claw automotive generator without magnetic strips according to claim 1, characterized in that: The claw polar arc coefficient of the octagonal sleeve (4) is 0.6~0.

7.

3. The eight-claw automotive generator without magnetic strips according to claim 1, characterized in that: The rectangular copper wire (8) has a polyimide insulation layer on its surface, and adjacent copper wires are isolated by the insulation layer.

4. The eight-claw automotive generator without magnetic strips according to claim 1, characterized in that: The stator core (21) is made of stacked silicon steel sheets, with insulating varnish applied between the sheets to reduce iron loss.

5. The eight-claw automotive generator without magnetic strips according to claim 1, characterized in that: The excitation winding (6) is made of flat copper wire.

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